TY - JOUR
T1 - Characterization of norovirus-associated traveler's diarrhea
AU - Ajami, N.
AU - Koo, H.
AU - Darkoh, C.
AU - Atmar, R. L.
AU - Okhuysen, P. C.
AU - Jiang, Z. D.
AU - Flores, J.
AU - DuPont, H. L.
N1 - Funding Information:
Financial support. The study was supported by discretionary funds from the Center for Infectious Disease, University of Texas School Of Public Health, and in part by grants from Public Health Service (grant DK 56338), which funds the Texas Gulf Coast Digestive Diseases Center in Houston, Texas. Support was also provided by the National Institute of Diabetes and Digestive and Kidney Diseases (grant 1K23DK084513–01 awarded to H.L.K.). Potential conflicts of interest. All authors: no conflicts.
PY - 2010/7/15
Y1 - 2010/7/15
N2 - Background. Traveler's diarrhea is the most common medical complaint of international visitors to developing regions. Previous findings suggested that noroviruses (NoVs) are an underappreciated cause of traveler's diarrhea. Methods. In the present study, we sought to define the presence of NoVs in 320 acute diarrheic stool samples collected from 299 US students who traveled to Guadalajara, Cuernavaca, or Puerto Vallarta, Mexico, during the period from 2007 through 2008. Conventional and quantitative real-time polymerase chain reaction assays were used to detect and determine NoV loads in stool samples. NoV strains were characterized by purification of viral RNA followed by sequencing of the viral capsid protein 1 gene. Sequences were compared using multiple sequence alignment, and phylogenetic trees were generated to evaluate the evolutionary relatedness of the viral strains associated with cases of traveler's diarrhea. Results. NoV RNA was detected in 30 (9.4%) of 320 samples. Twelve strains belonged to genogroup I, and 18 strains belonged to genogroup II. NoV prevalence was higher in the winter season than in the summer season (23% vs 7%, respectively; ). The cDNA viral loads of genogroup I viruses were found to be Pp.001 500-fold higher than those of genogroup II strains. Phylogenetic analysis revealed a diverse population of NoV strains over different locations and years. Conclusions. NoV strains are important causes of traveler's diarrhea in Mexico, especially during the wintertime, and US students in Mexico may represent a suitable group for future NoV vaccine efficacy trials.
AB - Background. Traveler's diarrhea is the most common medical complaint of international visitors to developing regions. Previous findings suggested that noroviruses (NoVs) are an underappreciated cause of traveler's diarrhea. Methods. In the present study, we sought to define the presence of NoVs in 320 acute diarrheic stool samples collected from 299 US students who traveled to Guadalajara, Cuernavaca, or Puerto Vallarta, Mexico, during the period from 2007 through 2008. Conventional and quantitative real-time polymerase chain reaction assays were used to detect and determine NoV loads in stool samples. NoV strains were characterized by purification of viral RNA followed by sequencing of the viral capsid protein 1 gene. Sequences were compared using multiple sequence alignment, and phylogenetic trees were generated to evaluate the evolutionary relatedness of the viral strains associated with cases of traveler's diarrhea. Results. NoV RNA was detected in 30 (9.4%) of 320 samples. Twelve strains belonged to genogroup I, and 18 strains belonged to genogroup II. NoV prevalence was higher in the winter season than in the summer season (23% vs 7%, respectively; ). The cDNA viral loads of genogroup I viruses were found to be Pp.001 500-fold higher than those of genogroup II strains. Phylogenetic analysis revealed a diverse population of NoV strains over different locations and years. Conclusions. NoV strains are important causes of traveler's diarrhea in Mexico, especially during the wintertime, and US students in Mexico may represent a suitable group for future NoV vaccine efficacy trials.
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U2 - 10.1086/653530
DO - 10.1086/653530
M3 - Article
C2 - 20540620
AN - SCOPUS:77954752402
SN - 1058-4838
VL - 51
SP - 123
EP - 130
JO - Clinical Infectious Diseases
JF - Clinical Infectious Diseases
IS - 2
ER -